Advertisers and content providers continue to grapple with how to optimize ads in online video, and contributing to the dialogue, this morning AOL is releasing research indicating that ads in short-form videos are more effective than ads in long-form. Based on research involving 800 participants, AOL and its research partner Qualvu found that ads in short-form video had a 25% higher brand recall, produced 42% higher purchase intent and were 26% more likely to be liked. Short-form video is defined as less than 10 minutes with long-form 10 minutes or longer.

In addition, the study says that ads in long-form videos more significantly detract from the viewers' experience and diminish the impression of advertisers. Specifically, long-form video ad viewers are 52% more likely to think the ad detracts from their experience, while almost half incorrectly believed they saw an ad at the end of the long-form video.

Importantly, the research also found that long-form viewers are displaying some of the same ad avoidance tactics, like doing something else during the playing of ads, that have long been used in TV. To mitigate this, respondents indicated that they would pay more attention to ads that are more targeted, funny and engaging.

It's worth remembering that AOL has an interest in demonstrating that short-form video is a superior advertising environment, as it maintains the largest library of premium short-form video, which drives its huge video syndication business. Still, with ad loads in long-form content steadily increasing and DVR use proliferating, it's no surprise that viewers are adapting their online behaviors. Advertisers and content providers need to take note of these trends and be careful not to simply turn the online video medium into TV, where ad-skipping has become routine behavior for so many people.